Plunger and staple driving structure for pneumatic stapling machines



June 29, 1954 A G |U|| F5 2,682,052

PLUNGER AND STARLE DRIVING STRUCTURE FOR PNEUMATIC STAPLING MACHINES Filed April 3, 1953 f @En n myn/mn .wlmi

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ATTORNEYS,

Patented June 29, 195:4

UNITED STATES PATENT OFFICE PLUNGER. AND STAPLE DRIVING S/TRUC- TURE FOR PNEUMATIC STAPLING MA- CHINES Claims. 1

My invention relates to pneumatic stapling machines and is specifically directed to means for fixing the staple driver to the piston which actuates it.

It is an object of my invention to provide a staple drive mechanism wherein the staple driver may be secured to the piston which actuates it and wherein the height and weight of the stapling machine may be maintained at a minimum. f

Other objects and advantages of my invention will become apparent to one skilled in the art from the following description and with reference to the accompanying sheet of drawings wherein like numerals are employed to designate like parts throughout the same and wherein:

Figure 1 is a view partly in section and partly in side elevation showing a pneumatic stapling machine of the type to which the instant invention is applicable and also showing one modification of the instant invention,

Figure 2 is a fragmentary sectional view of the novel staple driver1 and piston connection generally illustrated in Figure 1,

Figure 3 is a view similar to Figure 2 but showing a modification thereof,

Figure fi is a view similar to Figures 2 and 3 but showing yet another modification of my invention,

Figure 5 is a sectional view of one of the members employed in still another modification of my invention,

Figure 6 is a view generally similar to Figures 2, 3 and 4 but showing yet another modification of this invention,

Figure 7 is a fragmentary perspective of the staple driver employed with the modication of Figure 6,

Figure 8 is a fragmentary sectional view of another modification of this invention, and

Figure 9 is also a fragmentary sectional view of yet another modification of this invention.

In my copending application Serial No. 181,023, now Patent Number 2,671,214, and in my Patent No. 2,585,941 I have shown stapling machines in which I have emphasized the advantages of so arranging the staple drive mechanism that the staple driver is free of the piston which actuates it. In the arrangement of the patent and the copending application referred to, stress is laid upon the desirability of providing means ,to stop the piston while permitting the driver to advance by inertia, separate means being provided to stop the driver.

In my Patents Nos. 2,585,939, 2,585,940 and CJi 2,585,942 I have shown, however, other arrangements wherein the staple driver is pinned to the piston which actuates it. Certain advantages are obtained by arranging the piston and driver in the manner taught in these patents just referred to.

In still another copending application, Serial No. 345,489, I have disclosed a novel stapling machine incorporating an anvil which may be moved toward and away from the nose or nozzle of the machine. Although it is possible to arrange this stapling machine so that the staple driver is either free of its actuating piston or Xed thereto as may be desired, I have found that it is often preferable to secure the driver to the piston. The instant invention, and its .various modifications, are especially applicable in a stapling machine cf the type described in the copending application last mentioned.

In the instant invention I provide a novel manner of securing the staple driver to its actuating piston. In doing this I lose the free running advantage which is inherent inthe arrangements set forth in my copending application Serial No. 181,023, now Patent Number 2,671,214, and in my Patent 2,585,941. Nevertheless I have found that in some instances it isidesirable to secure the driver to the piston and in particular I have found that the means of the instant invention constitute an excellent construction for accomplishing this. The means of the instant invention also constitute an improvement over the various methods of pinning a driver to a piston as set forth in my Patents 2,585,939, 2,585,940 and 2,585,942.

Referring rst to Figure l I have there illustrated a stapling machine of the type to which this invention is particularly well suited. The stapling machine of Figure 1 comprises a body portion Ill, a handle II and a staple feed maga- Zine I2. The body I0 may comprise a cylinder I3 in which there is a piston Ili. In the bottom of the cylinder I3 I provide a rather large bumper I5 against which the piston Iii will seat upon completing its stroke.

A staple driver I6 is xed within a member Il which is secured within the piston IE5. The driver I6 is adapted to reciprocate within a drive track I8 which is defined by a pair of plates I9 and 20 which are preferably removably secured to the body of the stapling machine I9.

The feedmagazine I2 is adapted to force a series of staples 2l into position within the drive track I8 so that upon reciprocation of the driver I6 a staple will be discharged through the end of the nose or nozzle 22 defined by the plates I Ii and 20. There are several satisfactory feed mechanisms which will accomplish this and it is to be understood that the particular feed mechanism employed does not constitute a limitation of the present invention.

A spring 23 is seated within the cylinder I3 and also within a recess 24 provided around the member I1 within the piston I4. This spring urges the piston I4 against the cylinder head 25.

Air is admitted to the stapling machine through the coupling generally indicated at 2S. The trigger 21 and valve mechanism generally indicated at 22 control the admission of air to the cylinder behind the piston. It will be understood that upon actuation of the trigger 21 air will flow through the channel 29 into a recess 30 located behind the piston I4. This air will force the piston I4 against the bumper I5 whereby the driver I6 will be forced through the slot I8 so that it will drive a staple 2| out of the nozzle 22 and into the Work being stapled. A small groove in the cylinder wall is shown at SI and this connects the passage 29 with the recess 3i).

It is believed that the above description fully deiines an operative pneumatic stapling machine.

The instant invention resides in the manner of securing the staple driver I6 within the piston I4 in such a way that the spring 23 may seat within this piston. It is very important that the spring be able to seat within the piston for this enables the height, and therefore the weight, of the stapling machine to be maintained at a minimum.

Referring now to Figure 2 I shall describe one of the basic modication of my invention. In this ligure, as will be true throughout the specification, like numerals are employed to designate those parts which are generally shown in Figure l and just described. Figure 2, therefore, discloses a piston I4 having a recess 24 in which there is secured a member I1. In the particular modification here shown I have indicated that the member I1 is brazed within the piston Iii as indicated at 32.

The member I1 is provided with a slot 33 adapted to receive the staple driver I6. A pin 32 passes through the member I1 and driver I6 and securely holds the two together.

It is preferred that the embodiment of my invention shown in Figure 2 be made and assembled as follows. First I form a piston I4 having the recess 24. The center piece I1 is then separately formed and I prefer to provide it with a flange 35 as indicated. The slot 33 is then milled within the member I1 after which the member I1 is brazed within the recess 24 of the piston I4 as indicated at 32.

The next step in constructing the modification of Figure 2 is to drill through the assembled members I4 and I1 so as to form the holes 35 and 31 in the wall of the piston I4 and the hole 3S within the member I1. The driver IS is formed with a hole which will register with the hole 38 just formed in the member I1.

The driver I6 is then inserted within the slot 33 formed in the member I1 and the pin 34 is placed within the hole 38. This pin may be inserted through either of the holes 36 or 31. When the driver and piston are placed within the cylinder I3 it is contemplated that the loops of the spring 23 will serve to maintain the pin 34 in position.

The arrangement just described insures a solid connection between the member I1 and the piston I4 and also between the driver I5 and this member I1. At the same time the construction provides a recess within which the spring 23 may seat. This spring not only serves to return the piston Ill to its starting position after it is fired but it also serves to maintain the pin 34 within the hole 3d. This mode of securing the driver I5 to the piston I4 has proved Very satisfactory and is believed novel with me.

In Figure 3 I have shown an arrangement which is generally similar to that shown in Figure 2 and, therefore, corresponding parts have been designated by like reference nuInerals. In the arrangement of Figure 3, however, I attach the member El' to the piston I4 by means of a screw or the like 3S. This construction enables me to eliminate the holes and 31 in the wall of the piston Iii because it will be apparent that I can form the slot 3S and hole 38 within the member Ii prior to the time that it is screwed within the piston I4. It is again contemplated that the loops of the spring 23 will serve to maintain the pin within the hole 3S provided in the member l. Since, however, the driver will be pinned to the member I1 prior to the time that the member I'I is screwed within the piston I4, it will be possible to rivet or otherwise secure the pin 356 within its hole if this is desired.

In the mcdication of Figure e I have disclosed an arrangement wherein the centrally located member II is riveted to the piston i4 within the recess d thereof and wherein the member Il is so formed that the lower portion thereof will extend clear of the piston. This construction enables me to locate the pin 34 outside of the piston I. In some cases this makes it easier to replace the staple driver should this prove desirable. The riveted connection between the member il and the piston I4 is indicated at 4U. As mentioned, the hole 38 and its pin 34 are located in an extension Ila of the member I1, such extension depending from the piston. Again it will be observed that the spring 23 may surround the member I1 and be received within the recess 24 of the piston ICI.

Figure 5 illustrates a modification of my invention wherein the piston I4 and central fixture I1 are formed as a one piece casting. This casting might perhaps be made of powdered metal properly fused together as is known in the metallurgical art. This embodiment also makes use of the extension IIa described in connection with the showing oi Figure e.

In Figures 6 and 7 I have illustrated yet another embodiment of this invention. In these figures I provide the member I'I with the extension I'Ia and I also contemplate brazing this member within the piston I4 as indicated at 32 and as discussed in connection. with the showing or" Figure 2. The piston I4 is again provided with a recess adapted to receive the member I? and also the spring 23 above referred to. In the modification of Figure 6 the extension Ila is again provided with a slot 33 designed to receive the staple driver Iii. In this modification, however, the slot E3 has its upper limit defined by a hole lil which is drilled in the extension Ila. The driver IS is provided with a bead I6a which fits within this hole Il I.

When the driver I6 and bead Ia are slipped laterally to position within the slot 33 and hole iii, and the assembled driver i5, member I1 and piston I placed within the cylinder I3 so that the spring 23 is received in the recess 24, the

spring 23 will prevent the driver [6 from being displaced with respect to the member l1. At the same time, however, the bead la will hold the driver against longitudinal displacement with respect to the member il and piston lli.

Referring new to Figures 8 and 9 I have there illustrated other means by which the driver I5 may be secured to the piston it. In each of these modincations the driver It is formed with a head i2 and member Il is formed with a recess i3 adapted to receive this head. The vslot 33 extends through the member Il to the recess d3. In this way the driver may be slipped into position within the member Il by inserting it from the top. The members i6 and Il may then be secured to the piston le as indicated by the screws 44. It will be apparent that when the member Il is screwed into the position in the manner just described the driver It will be firmly fixed and clamped between the member I1 and the top of the piston M.

The embodiment of Figure 9 is very much like that of Figure 8 except that in this gure I have shown the member l'i as having a bore i5 into which there is placed resilient material 4S. This construction will permit some wobbling of the driver it as might be necessary in order to insure proper alignment with the staple drive track Iii. t will be obvious that in each of the embodiments or" Figures 8 and 9 the screws ill could be eliminated and the member I1, with the driver it and its head t2 seated therein, could be brazed or soldered within the piston It as generally indicated in Figure 2. In each of the embodiments of Figures 8 and 9 the spring 23 may seat within the piston ifi.

It will be apparent from the above description and from the drawings that the basic structure of my invention incorporates the use of a central member to which the iver may be fastened, the central member being in turn secured to the piston proper. I have found that by providing the piston Hl with the member l1 to which the driver is connected I am able to obtain a much more rigid connection of the driver I6 with the piston it. This, for example, has resulted in a better construction than that shown in my Patents Nos. 2,585,939, 2,585,940 and 2,585,942.

It is important that the connection between the driver i5 and piston I4 be a good one. When a staple gun, for example, is red empty so that the work being stapled oiers no resistance to the driver and piston, there is a severe strain placed upon the gun, particularly the connection between the driver and piston. In those guns wherein the driver is free of the piston this does not present so great a problem because separate means may be employed to stop the piston and the driver, the driver being free to advance after the piston has been stopped. A single means does not have to stop the combined Weight of the piston and its driver.

Where the free running driver feature is eliminated, however, it is obvious that a good connection must be effected between the driver I6 and the piston ifi in order to prevent the driver IB breaking from the piston. I have found that the embodiments of the instant invention as above set forth produce very rigid connections between the driver and piston which are not easily broken. It is believed that the use of the intermediate member il has made these rigid connections possible and it will be apparent that at the same time I have made it possible to seat the needed spring 23 within the piston so as t0 keep down the height and weight of the gun as is obviously desirable.

It will vbe'obvious to those skilled in the art thatrmodincations may be made in my invention without departing from the scope and spirit thereof, and while` I have shown my invention `as embodying :certain specific structures and arrangementsl do not intend to be limited to such exemplary structures and arrangements except :insofar asthey are specifically set forth in the sub-joined claims. v

Havingthus described my invention what I claim as .new and what I desire to protect by United States Letters Patent is:

1. In a pneumatic stapling machine having a staple driver actuated by a piston driven by air and returned by a spring, the improvement which comprises a connection between said driver and. said piston, said piston having a recess dening a piston head and side wall, said connection comprising a member intermediate said piston head and said driver, said driver seating within said intermediate member and said intermediate member being fixed to said piston head within said recess, and said spring surrounding said intermediate member and also seating within said recess.

2. The improvement of claim 1 in which the end of said intermediate member opposite said piston head is provided with a bore, said driver extending within said bore, and resilient material packed in said bore about said driver.

3. The improvement of claim 1 in which said intermediate member is slotted to receive said driver, and a pin passing through said intermediate member, said slot and said driver.

e. rIhe improvement of claim 3 in which said pin is located within said recess.

5. The improvement of claim 4 in which said piston side wall has holes registering with said pin, convolutions of said spring lying between said holes and said pin, whereby said spring maintains said pin Within said intermediate member and said driver.

6. In a pneumatic stapling machine having a staple driver actuated by a piston driven by air and returned by a spring, the improvement which comprises a connection between said driver and said piston, said connection being made through a member intermediate said driver and said piston, said intermediate member being iXed to said piston, said piston having a recess to receive said intermediate member, said spring surrounding said intermediate member and also seating within said recess, said intermediate member being slotted to receive said driver, and a pin passing through said intermediate member, said slot and said driver, said intermediate member extending out of said recess, and said pin being located in the extended portion of said intermediate member lying outside of said recess.

7. In a pneumatic stapling machine having a staple driver actuated by a piston driven by air and returned by a spring, the improvement which comprises a connection between said driver and said piston, said connection being made through a member intermediate said driver and said piston, said intermediate member being fired to said piston, said piston having a recess to receive said intermediate member, said spring surrounding said intermediate member and also seating within said recess, said intermediate member having a slot to receive said driver, said slot terminating in an enlarged opening, and said driver :havingran enlarged:` portion received saidfenlarged opening.

f 8.: The improvement, of-` claim 'Zfzinfwhichcsad ,enlarged ,-openingfcomprises `aygbore; extending through `said` intermediate member; 'whereby said driver and; enlarged :portion .,are;A planted-f1 within said intermediate member :Eromlthe sidethereof. t 9. The improvement of^c1ainr 8 nlwhich said intermediate. member* has; an. extended; portion lying outside uofasaid' recess; saidslot, andy bore being in said extended portion.

10.'` The improvement `laf. vclaim 7 :in which :said

a'enlarged opening fis a recessedz'area in that end of said intermediate.:member;k immediatelyad- .fjacentfsaid piston, the enlarged portion of said `driver'seating within said recessed area and abutting saidf piston,. whereby said driver and enlarged portion are placed within said intermediate member from the said end having the said recessed area.

References Cited in the file of this patent;

'UNITED STATES PATENTS 

